Web forming method and apparatus



Jan. 30, 1962 R. M. NEWMAN, JR

WEB FORMING METHOD AND APPARATUS 5 Sheets-Sheet 1 Filed Dec. 8, 1959 INVENTC'R RALPH M. NEWMAN, JR.

ATTORNEY Jan. 30, 1962 R. M. NEWMAN, JR

WEB FORMING METHOD AND APPARATUS 5 Sheets-Sheet 2 Filed Dec. 8, 1959 INVENTOR RALPH M. NEWMAN, JR

ATTORNEY Jan. 30, 1962 R. M. NEWMAN, JR

WEB FORMING METHOD AND APPARATUS 5 Sheets-Sheet 3 Filed Dec. 8, 1959 INVENTO, RALPH M. NEWMAN, JR

ATTORNEY;

Jan. 30, 1962 R. M. NEWMAN, JR 3,019,158

WEB FORMING METHOD AND APPARATUS Filed Dec. 8, 1959 5 Sheets-Sheet 4 INVENTOR RALPH M. NEWMAN, JR

ATTORNEY WEB FORMING METHOD AND APPARATUS Filed Dec. 8, 1959 5 Sheets-Sheet 5 INVENTOR RALPH M NEWMAN, JR 1 ATTORNEY 3,819,158 Patented Jan. 30, 1962 Free This invention relates to a method and apparatus for continuously forming webs and more particularly, to a method and apparatus for forming such a web from a fiber slurry or suspension.

Previous to this invention, the formation of webs from fiber slurries, particularly in the manufacture of paper and like products, has been accomplished in most instances either by the use of Fourdrinier machines or cylinder-type machines. In the Fourdrinier machine, the furnish or fibrous slurry is introduced onto a traveling wire from a head box and slice for passage over rollers and suction devices to extract the liquid from the deposited slurry. Cylinder-type machines, on the other hand, incorporate a rotatable perforate cylindrical drum partially immersed in a vat containing the fiber slurry to effect passage of the slurry through the drum leaving the fibers deposited on the drum exterior. In many types of cylinder machines the slurry is passed through the drum under the influence of the pressure head in the vat while in others, suction means are incorporated within the drum to draw the slurry through the drum periphery. Subsequently, in both of these basic types of machines, the fibrous web thus formed is passed through various drying, calendering or other finishing apparatus before the desired product is obtained.

While the apparatus or" the type aforementioned has met with considerable success in the paper making industry, several objectionable features are present in these available types of machines. For example, in Fourdrinier machines, the principal objection arises due to the high rate of speed at which the wire moves relative to the devices over which it travels, such as suction boxes and the like. Because of this relative, high speed movement, excessive wire stresses as well as wear due to friction require frequent replacement and repair of the wire and accordingly increases the maintenance expenses incurred by the use of such machines. Additionally, the wire must be supported at reasonably short intervals by rolls and as well, requires the use of various tensioning devices. In order to prevent upsetting the fiber formation on the wire, these rolls and like devices must be extremely accurately machined, therefore requiring high manufacturing costs. Also, in recent years, paper manufacturers have found it desirable to direct the furnish or slurry through the wire under pressure so that the fibers are deposited on the wire under the influence of a pressure head. However, such pressure formation has not worked out in practice due to the extreme stresses imposed on the forming wire and the lack of suitable means to overcome these stresses.

The cylinder machines on the other hand, eliminate the need for wires of the type used in Fourdrinier machines or at least alleviate the wire maintenance problems due to friction and the like as aforementioned. However, the cylinder-type machine presents a critical problem particularly in high speed operation, as a result of centrifugal force developed by rotation of the cylindrical perforate drum. Furthermore, since the fibers deposited on the exterior of the drum are immersed in the slurry, there is a strong tendency for the accreted fibers to be washed oil? as they leave the slurry. For these reasons, cylinder machines are limited to slow speed operations.

To achieve the beneficial results of the cylinder-type machine, i.e. the elimination of the wire wear, and at the same time overcome the problems incurred due to centrifugal force of the rotating cylinder, attempts have been made to form the web on the interior of a rotating perforate drum. In this respect, see for example French Patent 981,228 of 1951. Although this approach is desirable from the standpoint of meeting the above mentioned problems that are incurred in Fourrlrinier and cylinder type machines, it poses the particularly acute problem of removing the partially formed Web from the interior of the rotating drum. Because of this problem, this approach has been generally discarded except where relatively short lengths of web material are required.

Accordingly, an object of this invention is to provide a new and unique method and apparatus for forming continuous webs from fiber slurries by which the problems previously incurred are elfectively overcome.

A further object of this invention is that of providing an apparatus particularly suitable to pressure formation of a fibrous web from a slurry.

Another object of this invention is the provision of an apparatus of the type aforementioned by which a fiber slurry may be continuously deposited on the interior of a rotating drum, the liquid extracted therefrom and the accretion of fibers remaining on the interior of the drum removed as a continuous web for subsequent treatment.

A further object of this invention is that of providing an apparatus of the type referred to in which the centrifugal force developed by a rotating forming drum may be combined with the action of a vacuum to quickly and effectively remove substantially all of the liquid from the fiber suspension prior to removal of the partially fonned fibrous web from the forming drum.

Another object of this invention is the provision in an apparatus of the type referred to of extremely effective means for removing the partially formed fibrous web from the drum interior.

A still further object of this invention is to provide a new and improved method of removing a partially formed fibrous web from the interior of a rotating drum.

Other objects and further scope of applicability of the present invention will be apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description, while indicating preferred embodiments of the invention, is given by Way of illustration only, since it will demonstrate to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of this invention.

In general, the aforementioned objects are accomplished by providing a foraminous screen or other perforate inwardly facing cylindrical surface on the interior of a rotatable drum suitably braced and reinforced. A head box and slice are arranged interiorly of the drum for the purpose of depositing a fiber furnish or slurry on the interior of the screen. At a point on the drum circumference remote from the head box and slice, is located exteriorly of the drum a nozzle for directing high pressure fluid inwardly through the screen. A conveying means extends within the drum and terminates in a lip positioned adjacent to the screen and opposite from the nozzle so that the web is picked up by the conveyor as it is removed from the screen. The conveyor is curved gently in the direction of the drum axis to carry the web out of the drum interior and is formed having a plenum chamber opening through an apertured top wall so that pressurized fluid may be used to support the web on the conveyor. Further, the drum is exteriorly sealed within a housing and a suction chamber established therein between point of slurry deposit and web removal for the purpose of adding to the water extracting facility afforded centrifugal force developed by drum rotation.

A more complete understanding of the new improved web forming apparatus of this invention and its operation may be had by reference to the accompanying drawings, in which:

FIG. 1 is a side elevation of the apparatus of this invention;

FIG. 2 is a cross sectional plan view taken along line 22 of FIG. 1;

FIG. 3 is a cross sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is an enlarged fragmentary cross sectional view showing in detail, the new and improved means of this invention for removing the partially formed web from the interior of the rotating drum;

FIG. 5 is an enlarged fragmentary cross sectional elevation showing an alternative embodiment of the web conveying means of this invention; and

FIG. 6 is a partial cross section taken along line 6-6 of FIG. 5.

As shown in the drawings, apparatus of this invention includes a pair of front and rear frame assemblies generally designated by the numerals 10 and 12 respectively. These frame assemblies are substantially identical and each include a base member 14, a pair of vertical members 16 and 18 and a transverse cap member 20*. The front and rear frame assemblies 10 and 12 may be interconnected by suitable bracing (not shown) or alternatively may be independently anchored on a suitable support.

Centrally positioned between the front and rear frame assemblies 10 and 12 respectively is a rotatable forming drum generally designated by the numeral 22 in the drawings. The drum structure includes a pair of bearing rings 24 and 26, each having an axially extending bearing portion 28 and a radially outwardly sealing portion 30. Extending axially between the bearing rings 24 and 26 is a plurality of supporting blades or struts 32. These supporting blades are welded or otherwise anchored at their ends to the respective bearing rings and thus provide with the bearing rings the supporting structure of the forming drum. The remaining structure of the drum provides (the forming surface for the fibrous web and preferably includes an annular foraminous screen 34 backed up by winding wires 36, which in turn are welded or otherwise suitably fixed at the interior edge of the blades 32. To give the drum additional strength, annular rings may be formed by providing between the blades 32 a plurality of bracing members 38. The provision of the members 38 will further facilitate engagement of sealing devices with the exterior of the drum as will be more fully described hereinafter. The screen 34 is retained against wires 36 by any suitable means such as by wiring or the like (not shown) and secured against the bearing rings 26 and 26 by generally L-shaped rings 40. The rings 40 will further function as deckle rings since one flange thereof extends radially inwardly of the screne 34 and therefore will serve to mold or otherwise fashion the edges of the web formed on the screen so that they are straight and regular.

Although the foraminous forming screen '34 and the supporting structure incidental thereto is preferred, it is to be understood that other suitable drum structures could be used. In this respect, any perforate or porous wall, adequately supported to resist forming pressures and which will permit the passage of liquid but not fibers, will suffice.

The forming drum 22 is rotatably supported in its position between the frame assemblies 10 and 12 by a plurality of rollers 42 positioned at various places about the lower circumference of the drum and engageable with the bearing portions 28 of the rings 24 and 26 respectively. It will be noted that both the rollers 42 and the bearing portions 28 of the rings 24 and 26 are formed having complementing V-shaped surfaces to prevent axial displacement of the drum and the rollers. In addition, a plurality of hold down rollers 44 are mounted on the cap members 29 to prevent upward displacement of the drum.

A motor 46 is provided for driving the drum 22 through a spur gear 48, the teeth of which engage the teeth 49 provided on the interior of the bearing ring 26. It thus becomes apparent that the drum 22 is securely supported between the frame assemblies 19 and i2 and may be effectively driven at high speeds through the gear 43 engaging the teeth 49 on the interior of the bearing ring 26 without in any way interfering with access to the interior of the drum.

The drum 22 is positioned rotatably within a housing 56 supported between the front and rear frame assemblies 16 and 12. The housing is formed having a pair of sidewalls 52 centrally apentured to receive the drum and as can be seen in FIG. 2, which sidewalls fit closely against the radially extending sealing portion of the drum hearing rings 24 and 26. Although no particular sealing structure is shown between the rotatable drum and the housing 59 other than locating the walls 52 of the housing in close proximity to the sealing flanges 30, it will be apparent to those skilled in the art that any suitable sealing device may be used at this point so long as rotation of the drum is not unduly impeded. The lower portion of the housing 50 defines a sump chamber 54 in which liquid extracted from the fiber slurry is collected. A drainage pipe 56 is provided for draining any liquid so collected from this chamber. The lower portion of the housing 50 or chamber 54 is separated from the upper portion of the housing to define an upper chamber 58 by a sealing assembly generally designated by the numeral 69 and a nozzle and seal assembly generally designated by the numeral 62. Funther, a partial vacuum may be developed in the chamber 54 by exhausting air through pipes 63 leading from the chamber to a suction pump or the like (not shown). The chamber 58, on the other hand, is vented to atmosphere through a pipe 64.

The seal includes upper and lower sealing blades 65 and 66 pivotally mounted on a pair of shafts 68 and 70 respectively. Prefenably, the sealing blades are urged against the exterior surface of the forming d-rurn 22 under the influence of weights '72 and 74, though it will be understood that other means for eflecting the proper seal may be used. The lower sealing blade 66, in addition to engaging the outer periphery of the forming drum engages a resilient seal strip 76 which is fixed to the housing 50 such as by bracket 78 and continues downwardly and against the outer portion of the housing to form a trough from which a drain pipe 86 leads to facilitate removing any water or other liquid which may accumulate in this vicinity. Further, a nozzle 82 is disposed between the upper and lower sealing blades 65 and 66 to permit a spray of water between the blades.

A head box 84 of standard construction is suspended within the forming drum 22 from the transverse frame members 29 such as by angle brackets 86. The head box 84 includes a slurry of furnish inlet manifold 88 from which the furnish is fed through conduits 90 into a baffle chamber 92. This chamber is preferably under a head of fluid pressure developed by a suitable compressor (not shown) feeding through a nipple 93. Thus, the furnish is fed from the chamber 92 forwardly and downwardly past a pluraiity of distributor rolls 94 to a slice 96 from which it is deposited directly against the interior surface of the forming drum screen 34 under pressure. A flexible slice lip 98 is adjustably retained against the forming screen 34 by a plurality of adjusting screws 1% arranged at intervals across the Width of the slice. As aforementioned, this head box and slice arrangement in and of itself is standard and as such forms no part of the present invention.

Since the slice 96 opens to deposit the furnish on the forming screen 34 directly opposite from the upper and lower sealing strips 65 and 66 as well as the water spray nozzle 82, the principle under which the seal 60 operates to effect a complete fluid separation between the chambers 54 and 58 in the housing 50 can be readily understood. In other words, it will be apparent to those skilled in the art that the blades 65 and 66 in and of themselves would not be capable of effecting this seal because of the transverse blade 32 and the interrupted surface thus formed 011 the exterior of the forming drum. However, since the furnish is introduced on the interior of the forming screen 34 at this precise point and since the greatest percentage of liquid passes through the forming screen at this point, the desired seal is accomplished as a result of the blades 65 and 66 and nozzle 82 maintaining a sufficient amount of liquid about this point on the forming device to effect a liquid seal.

As shown in FIG. 3, the nozzle and seal assembly 62 is positioned exteriorly of the drum 22 and removed on the drum circtunference from the siice 96 so that the sector as defined by that portion of the drum between the slice 96 and the assembly 62 is suflicient to permit the desired liquid extraction and fiber formation or web 101 on the screen 34. structurally, the assembly 62, as best shown in FIG. 4 includes a pair of nozzles 102 and a pair of sealing strip groups 104 and 106 on either side thereof, each formed of a plurality of sealing strips 108. To overcome the problem of effectively sealing the drum from the exterior, it will be noted that each of the sealing strip groups 104 and 106 extend for a distance slightly greater than the spacing between the blades 32. In this manner, the nozzles 102 are effectively separated or sealed off from both chambers 54 and 58 in the housing 50 since at all times the sealing strips 108 are covering at least one of the blades 32. To separate the chamber 54 from the chamber 58, an additional seal strip 110 is mounted on the exterior of the assembly 62 and engageable with the interior of the wall of the housing 50.

A plurality of roller assemblies 112 are mounted in the housing 50 for the purpose of urging the sealing and nozzle assembly inwardly against the forming drum 22. Further, adjustment of the assembly 62 about the periphery of the drum 22 may be eifected by a rotatable rod 114 threadedly engageable within a sleeve 116 fixedly mounted to the assembly 62 and arranged to be driven through a worm gear 11% by worm shaft 120. Because of this arrangement, the nozzles 102 may be accurately adjusted about the circumference of the drum 22 to permit removal of the Web 101 at precisely the proper point of drum rotation.

For the purpose of conveyin the web 101 from the interior of the drum 22 to subsequent drying and finishing apparatus or the like, a discharge conveyor or chute 122 is provided. As shown in FIG. 4, the chute 122 terminates at its inner end in a smoothly curved lip 124 Which parallels the forming screen 34 and is positioned adjacent to the interior thereof opposite the nozzles 102. Since the web 101, of necessity, must be removed axially of the drum 22, the chute 122 is formed having a curved configuration of such characteristics that the web 101 may engage the lip 124 while moving radially from the drum interior and be conveyed in a path having an axial component of direction equal to or greater than the width of the drum Thus, as shown in FIGS. 1 and 2, the chute 12 2 curves downwardly and outwardly from the lip 124, and as well, is suitably banked so that the stresses placed on the Web 101 as it is conveyed on the chute are kept at a minimum. It will be understood, however, that the specific curve or path taken by the chute 122 is shown for illustrative purposes only and that other configurations could be used in this invention. It is to be noted further that while the lip 12 1 as well as the nozzles 102 are disposed horizontally, it is contemplated that these members could be arranged otherwise without departing from the true spirit and scope of this invention. For example, they could be positioned obliquely so as to remove the web progressively and thus possibly facilitate the transfer of the web from the drum to the chute.

In the form shown in FIGS. 1 through 4, the chute structure includes a plenum chamber 126 having a lower Wall 120, an upper wall 1301, and side walls 132. The sidewalls 132 extend upwardly past the upper wall so that they form with the upper wall an open top chute. The upper wall 130 is formed having a plurality of apertures 13d therein, so that a fluid medium such as steam or compressed air may be introduced into the chamber 126 and exhausted upwardly through the apertures 134. In this manner, the web 101 which is transferred from the forming drum 122 to the chute, is pneumatically suspended on the chute during its discharge from within the forming drum. The chute 122 may be retained in position by any suitable means, and as shown in the drawings is suspended from the transverse frame members 20 by brackets 136 and anchored at the frame base members 14 such as by brackets 138. However, other means for suspending the chute 122 properly with respect to the drum interior may be used.

In operation, the furnish is fed through the slice )6 and deposited on the interior surface of the forming screen 34 of the rotating drum under the infiuence of the pressure head in the head box 84. Because the screen 34 is Well supported by the winding wires 36, blades 32 and members 33, there will be little tendency for the screen to sag, bend or otherwise be harmed in any manner by the forming pressures exerted thereagainst. Also, no stresses are placed on the screen due to friction since there is no movement thereof with respect to its supporting structure. The rotational speed of the drum 22 is sufllcient to develop a substantial centrifugal force tending to urge the slurry and deposited or collected fibers outwardly against the screen 34. In addition, however, due to the sealing function of the seal 60 and the seal and nozzle assembly 62, a vacuum may be created in the chamber 54 such as by withdrawing air through the pipes 63. Thus, the liquid from the slurry is forced through the screen 344 due to the combined effects of centrifugal force and the vacuum in the chamber 54. Although the greatest percentage of water extraction will occur in the vicinity of the slice 96, the extraction occurs continuously while the web is in contact with the screen 34 between the slice 96 and the assembly 62 and thus adjacent to the chamber 54.

As the drum 22 continues to rotate, the web 101 is carried around on the interior thereof until the seal 104 is reache Immediately thereafter, the web is removed from the forming screen 3d under the influence of a high pressure blast of steam or air emanating from the nozzles 1432. Since the nozzles are located directly opposite the screen from the discharge chute lip 124, the web is gently folded over the lip 124 and deposited on the chute upper wall 136 where under the influence of steam or air being ejected through the holes 134 therein it is floated downwardly and outwardly from the interior of the drum. Thereafter, the partially formed web from which substantially all of the Water has been removed may be transferred to conventional apparatus for subsequent finishing and treatment.

A modified form of the chute 102 is shown in FIGS. 5 and 6 of the drawings, In this instance, the chute includes a bottom wall 140, a pair of side walls 142 and a top wall 144 to define a plenum chamber 146 and differs from the embodiment as shown in FIGS. 1 through 4 in that the upper wall is formed having a plurality of transverse pockets 14 Positioned concentrically within the pockets are rolls 150 having shaft extensions 15.2 journaled in bearings 154. The bearings are suitably fixed to L-shaped runners 156 extending along each side of the chute and attached to bracket members 158 which in turn are welded or otherwise afiixed to the bottom Wall 140.

It will be noted that the pockets 148 open upwardly along the line intersection of chords established by the 4 plane of the top wall 144 and that the upper portion of the circumferential surface of the rolls 15% extend past the top wall 144. In this manner, the rolls are positioned to support the web 11H prior to engagement thereof with the stationary top Wall 144.

As in the previous embodiment, the plenum chamber 146 is adapted to receive fluid under pressure such as compressed air or steam through suitable conduits such as a nipple 160 and further, the top wall 144 as well as the pockets 148 therein are formed having apertures 162 to pneumatically support or float the web 101 on the chute. It will be noted, however, that in addition to the apertures 162, nozzles 164 are positioned on the upstream side of the pockets 148 and arranged to direct steam or air from the plenum chamber against the rolls 15%. In this manner, the rolls 150 are gently rotated and thereby substantially eliminate the possibility of the moving web 101 coming in contact with a stationary surface since the upper roll surface extend slightly past the upper wall 144 as aforementioned. Although, in FIG. 5, the moving web 101 is shown following the contour of the conveyor surface, it is contemplated that by properly regulating the flotation pressure or the fluid pressure in the plenum chamber 146, the web will be suspended in gentle catenaries, virtually unsagging and in a substantially unstressed condition. Moreover, while rolls 150 are shown to be cylindrical, it will be obvious to those familiar in this art that conical rolls can be used to achieve effective conveying along the curved chute. In other words, by increasing the diameter of the rolls toward the outside of the curve, the increased distance traveled by the outside of the web is compensated for in a manner well-known in the conveying roll art.

Thus, it will be seen that by this invention an extremely effective apparatus is provided for continuously forming a fibrous web from an aqueous suspension of fibers. It will be noted that the forming screen 34 is adequately supported on the drum 22 in such a manner that the entire operation may be effected without in any way bending, flexing or otherwise stressing the forming screen to cause wear and other damage thereto. Accordingly, high formation pressures may be used. Further, and perhaps most significantly, the combined advantages of suction and centrifugal force are taken advantage of to obtain a high degree of water extraction in a brief period of time. Moreover, because the effects of the vacuum and centrifugal force are combined, the need for a high vacuum and elaborate seal is not needed.

It will be noted further that because of the fluid discharge nozzles in the top wall of the chute plenum chamber the partially formed and still delicate web is removed from the wire substantially by fluid mediums. First, the blast of steam emanating from the nozzles 102 removes the web from the wire 34 in a manner such that no damage is imparted thereto, and then the gradual curving and slopping of the chute 122 and as well, the fluid suspension of the web thereon results in no deleterious effects to the web.

Thus, the unique structural arrangements and methods referred to above, as well as any other features inherent in the new and improved web forming apparatus of this invention as can be seen completely fill the aforementioned objectives and generally improve upon the apparatus of this type presently available. It is to be further understood that since many possible changes can be made in the web forming apparatus of this invention without in any way departing from the spirit and scope thereof as defined in the appending claims.

I claim:

1. An apparatus for forming a continuous fibrous web comprising: a rotatable drum having a foraminous cylindrical wall; means for depositing a fiber slurry on the interior of said wall, whereby rotation of said drum effects liquid extraction from said slurry leaving a fibrous web on the interior of said wall; a chute having a portion positioned inside and adjacent to said drum wall, said f5 chute including bottom, side and top walls defining a plenum chamber adapted to receive fluid under pressure, said top wall being formed having apertures for discharging said fluid upwardly to support said web; and means for directing a jet of fluid inwardly through said drum to transfer the web of the interior of said drum to said chute.

2. An apparatus for forming a continuous fibrous web comprising: a rotatable drum having a foraminous cylindrical wall; means for depositing a fiber slurry on the interior of said wall, whereby rotation of said drum effects liquid extraction from said slurry leaving a fibrous web on the interior of said wall; a chute having a portion positioned inside and adjacent to said drum wall, said chute including bottom, top and side walls defining a plenum chamber adapted to receive fluid under pressure, said top wall being perforate and formed having a plurality of open top transverse pockets; and rotatable rolls supported within said pockets, the circumferential surface of said rolls extending upwardly past said top wall; and means for directing a jet of fluid inwardly through said drum to transfer the web of the interior of said drum to said chute.

3. The apparatus recited in claim 2 including nozzles extending through the upstream side of said pockets whereby steam from said plenum chamber is impinged against the surface of said rolls to impart rotation thereto.

4. An apparatus for forming a continuous fibrous web comprising: a rotatable drum having a foraminous cylindrical wall; means for depositing a fiber slurry on the interior of said wall; a housing positioned about said drum; means for producing a reduced pressure between said drum and said housing, whereby liquid passes from the slurry on the interior of said drum wall to said housing under the combined effects of centrifugal force due to rotation of said drum and the reduced pressure to leave a fibrous web on the interior of said drum wall; and means for continuously removing said web from the interior of said drum wall.

5. The combination recited in claim 4 in which said means for producing a reduced pressure includes seal means between said drum and said housing to define a chamber in said housing extending between said slurry depositing means and said web removing means.

6. The combination recited in claim 4 in which said means for continuously removing said web from the interior of said drum Wall comprises a chute having a lip portion positioned inside and adjacent to said drum wall; and means for directing a jet of fluid inwardly through said drum wall to transfer the web from the interior of said drum onto said lip portion.

7. The method of forming a continuous web from a fiber slurry comprising: pressure forming a fiber accretion to establish a web on the inside of a rotating perforate drum; extracting excess liquid from said web under the combined influence of centrifugal force and suction; directing a jet of fluid under pressure against the exterior of the drum to remove the web inwardly therefrom; and conveying the web out of the drum On a generally upwardly directed fluid current.

8. The method of removing a fibrous web from the interior of a perforate drum comprising: separating the web from the drum under the influence of a fluid jet; and conveying the web from the drum interior on a current of compressible fluid.

References Cited in the file of this patent UNITED STATES PATENTS 1,531,482 Hang Mar. 31, 1925 1,885,334 Darrah' Nov. 1, 1932 FOREIGN PATENTS 981,228 France May 23, 1951 

1. AN APPARATUS FOR FORMING A CONTINUOUS FIBROUS WEB COMPRISING: A ROTATABLE DRUM HAVING A FORAMINOUS CYLINDRICAL WALL; MEANS FOR DEPOSITING A FIBER SLURRY ON THE INTERIOR OF SAID WALL, WHEREBY ROTATION OF SAID DRUM EFFECTS LIQUID EXTRACTION FROM SAID SLURRY LEAVING A FIBROUS WEB ON THE INTERIOR OF SAID WALL; A CHUTE HAVING A PORTION POSITIONED INSIDE AND ADJACENT TO SAID DRUM WALL, SAID CHUTE INCLUDING BOTTOM, SIDE AND TOP WALLS DEFINING A PLENUM CHAMBER ADAPTED TO RECEIVE FLUID UNDER PRESSURE, SAID TOP WALL BEING FORMED HAVING APERTURES FOR DISCHARGING SAID FLUID UPWARDLY TO SUPPORT SAID WEB; AND MEANS FOR DIRECTING A JET OF FLUID INWARDLY THROUGH SAID DRUM TO TRANSFER THE WEB OF THE INTERIOR OF SAID DRUM TO SAID CHUTE. 